Memory card reader body with protective mesh on both sides

ABSTRACT

A memory card reader body includes proposed, on an internal face, a receiving recess to receive a memory card connector. The receiving recess has electrically conductive tracks forming a protective mesh for the memory card connector. The conductive tracks are such that they also extend on an external face of the memory card reader body through vias passing through the internal and external faces.

1. FIELD OF THE INVENTION

The invention comes within the field of memory card reader devicescomprising an integrated circuit board. These memory cards (MCs) arealso called smartcards. Such devices are used for example in manyapparatuses such as payment terminals, authentication devices oridentification devices or again content-reading devices.

More specifically, the invention relates to the securing of a memorycard reader body comprising a memory card connector to be mounted in amemory card reader terminal.

2. TECHNOLOGICAL BACKGROUND

We shall strive more particularly in the rest of this document todescribe the problems and issues existing in the field of electronicpayment terminals that confronted the inventors of the present patentapplication. The invention is of course not limited to this particularfield of application but is of interest for all types of terminals thatcan include a memory card reader and have to face proximate or similarproblems and issues.

In addition to a memory card reader, a memory card reader terminalcomprises a certain number of components such as a keypad, a screen, oneor more processors, a memory, an electrical power source.

For many years now, memory card reader terminals have seen a greatincrease in their functions. This is especially true of paymentterminals. Thus, in addition to the payment function, the terminalsembed network communications functions, contactless card detectionfunctions, token (for example loyalty token) management functions, etc.

In addition to the great increase in such auxiliary functions, memorycard reader terminals must withstand various attacks or attempts atfraud to which they are frequently subjected.

Of the aspects related to terminal security, manufacturers in thissector are more particularly interested in protecting the memory cardreader. The fact is that a memory card reader is still a relatively weaklink in the memory card reader terminal especially because the memorycard reader has a slot for the insertion of the memory card, and thisslot makes the interior of the terminal accessible from the exterior.More particularly, attackers seek to obtain access to the memory cardconnector. The memory card connector is that part of the memory cardreader that makes contact with the chip or the microprocessor embeddedin the memory card.

Referring to FIG. 1, a classic assembly of a memory card reader isdescribed. This memory card reader comprises a memory card reader body10 provided with an insertion slot 11 for inserting a memory card. Thememory card connector is directly integrated into the memory cardreader. It comprises connection pins 12 for connection to the printedcircuit board (PCB) 13. The PCB 13 also has electronic components 14.The assembly can also include a protective cover 15 that is to bemounted on the reader body, which is itself to be mounted on the PCBthrough fastening lugs.

When a malicious person succeeds in accessing a memory card connector,he can then envisage the intercepting or reading of data exchangedbetween the chip or the microprocessor of the memory card and theprocessor of the memory card reader terminal. Among the pieces of dataintercepted, we can cite especially the secret code entered by thecustomer when the secret code is requested. This secret code can beconveyed without encryption in certain smartcards. These intrusions cantake the form of drilling, scratching or any other intrusive techniqueaimed at shorting, cutting and/or modifying the characteristics ofsensitive electrical signals without in any way blocking the terminal(such blocking would make it impossible to carry out any subsequentfraudulent manipulation).

Many efforts have therefore been made to secure memory card readers.Thus, for example, memory card readers are provided with an electricalmesh protection triggered at electrical levels. This protection usesfine, adjacent electrical tracks at least partially covering the part tobe protected. For example, one track can be connected to a connectionpin of an active signal and the other track can be connected to aconnection pin connected to ground. When an object seeks to penetratethe protection enclosure or chamber, a cut-off or a short-circuit isproduced causing the terminal to be put out of service. The intrusionscan be detected upon levels of voltage or according to the compliance ofthe signals travelling through these tracks.

As illustrated in FIGS. 2 and 3, the memory card reader body 10 isprovided with a receiving recess 18 for receiving the memory cardconnector 16. The receiving recess 18 comprises electrically conductivetracks 20. This is a thermoplastic injection-molded part into which theelectronic circuit tracks 20 are integrated in three dimensions duringinjection. Such a receiving recess is here below called an MID (MoldedInterconnect Device) receiving recess or MID part. The 3D conductivetracks of the MID reception housing act as protective meshes for thememory card connector, especially the memory card I/O (Input/Output)signals travelling between the memory card (smartcard) and the memorycard connector. The conductive tracks take the form of loops, eachextremity of which ends in a connection pin (or a contact pin). Thedifferent connection pins illustrated here are grouped together in acontact zone 22.

To integrate the conductive tracks within the part, a laser etchingtechnique is used for example. Among the known techniques of laseretching, the technique of using a thermoplastic material doped with aplastic metal additive activated by means of a laser is used (this isthe technique known as the LDS (Laser Direct Structuring) technique).

Despite the protection measures developed to date, intrusions into thememory card reader body are still being detected. These protectionmeasures do not seem to be sufficiently dissuasive. In particular, thesystem of conductive tracks forming a protection mesh offers a solutionwith only a limited level of protection

There is a need to provide a solution that further reinforces the levelof security of the memory card readers, especially by increasing thetime needed to access the sensitive electrical signals of the memorycard reader.

3. SUMMARY OF THE INVENTION

In one particular embodiment of the invention, a memory card reader bodyis proposed comprising, on an internal face, a receiving recess toreceive a memory card connector, the receiving recess comprising atleast one electrically conductive track forming a protective mesh forthe memory card connector, said at least one electrically conductivetrack extending also on an external face of the memory card reader bodyby means of at least one via passing through said internal and externalfaces.

The term “via” is understood to mean an electrically conductive holethat provides the electrical link for one or more conductive tracksbetween the internal face and the external face of the memory cardreader body.

Thus, by extending the conductive track or tracks on the external faceof the memory card reader body, the protection mesh according to theinvention has a protection surface greater than that of prior artsolutions, reducing the possibilities of intrusion by malicious thirdparties (especially by machining the external face). Indeed, the greaterthe surface of the conductive track, the greater the chances ofdetecting fraudulent intrusion. It therefore becomes even more difficultto access the sensitive signals of the memory card reader withouttriggering a blockage of the reader.

The general principle of the invention therefore relies on theapplication of an electrical protection mesh configured to be on bothsides, improving the level of security against any intrusion bymalicious third parties.

According to one particular aspect of the invention, the memory cardreader body comprises at least one electrically conductive track of afirst type (for example to conduct an active signal), each extremity ofwhich is terminated by a connection pin situated on the internal face,said electrically conductive track of a first type extending from theinternal face towards the external face through a first electricallyconductive through hole and from the external face towards the internalface through a second electrically conductive through hole.

According to one particular aspect of the invention, the memory cardreader body furthermore comprises at least one electrically conductivetrack of a second type (through the ground), each extremity of which isterminated by a connection pin situated on the internal face, said atleast one electrically conductive track of a certain type extending fromthe internal face to the external face through a third electricallyconductive through hole and from the external face to the internal facethrough a fourth electrically conductive through hole.

According to one particularly advantageous characteristics in terms ofsecurity, the external face is covered with a thermosetting (orthermoset) resin.

Thus, it is made very difficult to access sensitive signals through theexternal face without breaking the electrically conductive tracks.Indeed, the fact that a thermosetting (or thermoset) resin is both hardand brittle makes the conductive tracks easy to break during anintrusion by soldering for example. It is therefore difficult to accessthe tracks without breaking them. Just like the thermosetting resin, anepoxy or polyurethane type resin can be envisaged.

According to one variant of the invention, the external face is coveredwith a thermoplastic resin.

Such a resin also reinforces the level of security.

According to one particular characteristic, the memory card reader bodyfurthermore comprises a protective cover mounted on the external face.

A drilling of the cover could lead to a deterioration of the electricaltracks and hence to the terminal being put out of service. The level ofsecurity is therefore increased.

According to one particular characteristic, said protective cover issealed to the external face by means of a thermosetting glue orcyanoacrylate glue.

Thus, it is made even more difficult to access to the sensitive signalswithout breaking the conductive tracks. Indeed, the fact of trying toremove the cover and damage it leads to the deterioration of thethermosetting glue or cyanoacrylate glue as well of the conductivetracks situated beneath this glue. This characteristic further increasesthe level of security against any malicious intrusion. It must be notedthat the cover can be of the thermoset, thermoplastic or metal type. Inthe case of a metal cover, it is necessary to provide for a thickness ofglue or resin great enough to prevent any interference with theconductive tracks.

According to one particular characteristic, said internal face and/orsaid external face has at least one area in relief or embossed on whichsaid at least one electrically conductive track extends.

Tracks with a 3D structure are thus obtained, reducing the possibilityof machining the external face of the memory card reader. Access to thesensitive signals is difficult because the conductive tracks need to beaccessed very slowly. The intrusion time is even further increased.

According to one particular advantageous characteristic, said at leastone electrically conductive track takes the form of a loop of adetermined geometrical shape.

Another embodiment of the invention proposes a memory card readercomprising the memory card body mentioned here above (in any one of itsdifferent embodiments).

Another embodiment of the invention proposes a terminal comprising theabove-mentioned memory card reader body (in any one of its differentembodiments).

Another embodiment of the invention proposes a method for manufacturinga protective mesh of a memory card connector for a memory card readerbody comprising:

-   -   the defining of a geometrical shape of at least one electrically        conductive track extending on the internal and external faces of        said memory card reader body by means of at least through via        passing through said internal and external faces;    -   the defining of a location of said at least one through via;    -   the obtaining of said at least one conductive track and said at        least one through via on the memory card reader body.

The protective mesh thus formed comprises conductive tracks on bothsides. The protective surface is increased as compared with theprior-art solutions, reducing the possibilities of external intrusions.The step for obtaining said at least one conductive track can be done bymeans of a laser-etching technique, for example an LSD technique. Thestep for obtaining at least one through via can be done by mechanicaldrilling or by a molding of the memory card reader body.

4. LIST OF FIGURES

Other features and characteristics of the invention shall appear fromthe following description, given by way of an indicative andnon-exhaustive example, and from the appended drawings of which:

FIG. 1, already described with reference to the prior art, shows aclassic example of the architecture of a memory card reader beforeassembly;

FIGS. 2 and 3, already described with reference to the prior art,present an example of a classic architecture of a memory card readerbody provided with a memory card connector;

FIGS. 4A and 4B present a top view and a bottom view of a memory cardreader body according to one particular embodiment of the invention;

FIGS. 5A, 5B, 5C, 5D each illustrate a simplified example of theelectrical diagrams of a protective mesh according to the invention,comprising four through vias;

FIG. 6 illustrates another simplified example of a schematic electricaldiagram of a protective mesh according to the invention, comprising sixthrough vias.

FIG. 7 illustrates the memory card reader body of FIGS. 4A and 4Bprovided with a protective cover according to one particular embodimentof the invention.

5. DETAILED DESCRIPTION

In all the figures of present document, the identical elements and stepsare designated by one and the same numerical reference.

We shall strive more particularly in the following description todescribe the invention in the context of electronic payment terminals.The invention of course is not limited to this particular field ofapplication but is of interest for any type of terminal that can includea memory card reader.

The general principle of the invention relies on the implementing of anelectrical protective mesh configured on both sides on the memory cardreader body as illustrated in FIGS. 4A and 4B.

The top view illustration in FIG. 4A shows the internal face of a memorycard reader body 100 and the top view illustrated in FIG. 4B shows theexternal face of the memory card reader body 100 according to oneparticular embodiment of the invention. The internal face is the face towhich the connector of said memory card gets attached.

The memory card reader body 100, which has a generally rectangularparallelepiped shape, comprises a receiving recess 180 on its internalface for receiving a memory card connector. The receiving recess 180 hasa pre-determined volume shape: it enables protection of the memory cardconnector from external intrusion while at the same time creating thespace needed for the insertion and the reading of a smartcard type ofmemory card. The receiving recess 180 comprises a plurality ofelectrically conductive tracks 200 forming a protective mesh for thememory card connector. As illustrated in the figure, the conductivetracks 200 are laid out on the internal face in such a way that theprotective mesh generally covers the surface of the receiving recess 180that is to receive the memory card connector. Each conductive tracktakes the form of a loop, each end of which terminates in a contact pin(or connection pin).

The receiving recess 180 furthermore comprises, on its internal surface,a contact zone (or connection zone) 220 in which the contact pins of theprotective mesh are grouped together. The contact zone 220 is intendedfor connection to the memory card connector. Once the memory cardconnector is integrated into the receiving recess 180, the contact pinsare connected to the electronic circuit, which ensures the operation ofthe electronic payment terminal, by means of an elastomer connector, forexample of the Zebra (registered mark) type. For example, the contactzone comprises six contact pins 220 as shown in FIG. 4A.

According to the invention, the conductive tracks 200 extend withoutinterruption on the external face of the memory card reader body 100 bymeans of electrically conductive through holes (also called vias herebelow) so as to extend the protective mesh from the internal facetowards the external face of the memory card reader body 100. Thethrough vias are illustrated by the encircled area referenced 150. Eachvia is a through hole providing the electrical link from a conductivetrack of the internal face (the “front face) towards the external face(the “back” face” or from the external face (the “back” face) towardsthe internal face (the “front” face). Thus; since the protective mesh isdual-faced (i.e. “front/back)), it has a protective surface that isgreater than that of the prior art solutions, reducing the possibilitiesof intrusion by malicious third parties (especially by the machining ofthe external face).

The vias in the present example are grouped together within a same areaof the memory card reader body 100. Naturally, this is an illustratoryexample and other configurations can be envisaged without departing fromthe context of the invention. For example, the vias can be distributeddisparately on the faces of the memory card reader body 100.

The conductive tracks 200 are laid out on the external face in such away that the protective mesh appreciably covers the entire externalsurface of the memory card reader body. Indeed, the greater the surfacecovered by the conductive tracks 200, the greater is the level ofdetection of intrusions. The tracks have a geometrically pre-determinedshape.

The conductive tracks 200 are printed on both faces of the memory cardreader body 100 by means of a laser-etching technique such as the LDStechnique for example.

In the example illustrated herein, the receiving recess 180 comprisestwo conductive loops: a first type of loop dedicated to the transmissionof the active input/output signal (denoted as I/O in the figure) and asecond type of loop dedicated to setting up a reference potential, alsocalled a ground (denoted as GND in the figure). As explained furtherabove, each loop extremity terminates in a connection pin.

The first I/O conductive loop extends without interruption from theinternal face to the external face of the reader body by means of afirst through via 150 ₂ and from the external face to the internal faceby means of a second through via 150.

The second conductive loop GND extends without interruption from theinternal face to the external face of the reader body by means of athird through via 150 ₁ and from the external face to the internal faceby means of a fourth through via 150 ₄.

In order to increase the chances of detecting fraudulent intrusion, thesurface of the memory card reader body is designed so as to have, on itsexternal face and/or its internal face, one or more features in reliefon which there extend the electrical tracks 200. These features inrelief can take the form of breaks or steps 160 thus enabling theforming of protective mesh with a 3D structure.

We refer now to FIGS. 5A, 5B, 5C and 5D each of which illustrates anexample of a simplified electrical diagram of a protective meshaccording to the invention, implementing four through vias. This is aprotective mesh situated on the external face of the memory card readerbody.

Referring to FIG. 5A:

-   -   the conductive track 10 a which corresponds to the input-output        signal I/O extends without interruption from the internal face        to the external face of the reader body in passing through the        through vias 30 a ₂ and 30 a ₃ and    -   the conductive track 20 a extends without interruption from the        internal face to the external face of the reader body in passing        through the through vias 30 a ₁ and 30 a ₄. Referring to FIG.        5B:    -   the conductive track 10 b which corresponds to the input-output        signal I/O extends without interruption from the internal face        to the external face of the reader body in passing through the        through vias 30 b ₂ and 30 b ₃ and    -   the conductive track 20 b extends without interruption from the        internal face to the external face of the reader body in passing        through the through vias 30 b ₁ and 30 b ₄. Referring to FIG.        5C:    -   the conductive track 10 c which corresponds to the input-output        signal I/O extends without interruption from the internal face        to the external face of the reader body in passing through the        through vias 30 c ₂ and 30 c ₃ and    -   the conductive track 20 c extends without interruption from the        internal face to the external face of the reader body in passing        through the through vias 30 c ₁ and 30 c ₄. Referring to FIG.        5D:    -   the conductive track 10 d which corresponds to the input-output        signal I/O extends without interruption from the internal face        to the external face of the reader body in passing through the        through vias 30 d ₂ and 30 d ₃ and    -   the conductive track 20 d extends without interruption from the        internal face to the external face of the reader body in passing        through the through vias 30 d ₁ and 30 d ₄.

In these configurations, the reader body has a set of four through viasand two conductive loops.

It will be understood that, by means of the through vias, the conductiveloop I/O and the conductive loop GND traditionally laid out on theinternal face of the memory card reader body are extended at leastpartially on the external face of said body.

FIG. 6 illustrates another example of a simplified electrical diagram ofa protective mesh according to the invention implementing six throughvias.

The conductive track 70 represents the ground and passes through thethrough vias 80 ₁ and 80 ₄. The conductive track 60 represents theactive input-output I/O signal. The conductive track 60 consists of afirst track portion 60 ₁ (Mesh In) situated on the external face of asecond track part 60 ₂ situated on the internal face of a third trackpart 60 ₃ (Mesh Out) situated on the external face. The passages of thetrack 60 from the internal face to the external face or the externalface to the internal face are provided by through vias 80 ₂, 80 ₄, 80 ₆,80 ₆. The second track part 60 ₂ forms a bridge between the internalface enabling the electrical connection of the first and third trackparts situated on the external face of the memory card reader body. Thisparticular configuration further slows down attacks by malicious thirdparties because it is not possible, by shorting a track part (or looppart), to deactivate the entire track of (or the entire loop).

This particular solution furthermore shows that by increasing the numberof through vias while preserving the number of signals or loops (oneground and one I/O signal), the number of electrical configurations thatcan be envisaged increases in a combinatory manner.

These are of course examples given purely by way of an illustration.Other electrical configurations based on the same principle can beenvisaged without departing from the framework of the invention.

In addition, the external face of the memory card reader body 100 iscovered with an opaque thermosetting protective resin (for example atwo-component epoxy resin of the LOCTITE 9497, LOCTITE 9466 or LOCTITE9464 type). Thus, accessing sensitive signals through the external facewithout breaking the conductive tracks is made extremely difficult.Indeed, a thermosetting resin is both hard and brittle. The opaquenessof the resin makes the conductive tracks non-visible through this resin.A thermoplastic protective resin can also be envisaged as a variant ofimplementation, but it nevertheless has the defect of being easilydeteriorated by heat. An acrylate type resin fulfilling the samefunction can also be used within the framework of the invention.

As illustrated in FIG. 7, the memory card reader body 100 can include aprotective cover 700 mounted on its external face. The cover can besealed to the external face by means of a thermosetting glue orcyanoacrylate glue (for example of the CYANO 406 type). The cover can bemade out of thermosetting or thermoplastic material. It is also possibleto envisage making the cover out of metal. In this case, it is necessaryto plan for a thickness of glue or resin that is great enough to preventany interference between the cover and the conductive tracks.

Those skilled in the art will choose the material of the reader body (atleast on its external face side) so that it is compatible in terms ofadhesion with the resin or the glue used to protect the reader body.Similarly, the material of the cover will be chosen in such a way thatit is compatible with the resin or the glue used.

Finally, we describe here below the main steps of the method formanufacturing a protective mesh for a memory card reader body accordingto one particular embodiment of the invention. First of all, ageometrical shape is defined for the electrically conductive tracksextending on the internal and external faces of the memory card readerbody. The location of the vias passing through said internal andexternal faces is also defined. Then, said conductive tracks are made bymeans of a laser-etching technique (LSD for example) on the internal andexternal faces of the memory card reader body along with the throughvias, using a mechanical drilling or laser drilling operation. Theprotective mesh thus formed includes conductive tracks on both sides.The protection surface is thereby increased as compared with the priorart solutions, reducing the possibilities of external intrusion. It mustbe noted that the geometrical shape of the tracks and the location ofthe vias can be chosen respectively from among a plurality ofpredetermined geometrical shapes and a plurality of predeterminedlocations. This makes it external intrusions even more difficult tocarry out.

1. A memory card reader body comprising: an internal face and anexternal face; on the internal face, a receiving recess to receive amemory card connector, the receiving recess comprising at least oneelectrically conductive track forming a protective mesh for the memorycard connector wherein said at least one electrically conductive trackalso extends the external face of the memory card reader body through atleast one via passing through said internal and external faces.
 2. Thememory card reader body according to claim 1, comprising at least oneelectrically conductive track of an active-signal-conducting type, eachextremity of which is terminated by a connection pin situated on theinternal face, said electrically conductive track of anactive-signal-conducting type extending from the internal face towardsthe external face through a first electrically conductive through holeand from the external face towards the internal face through a secondelectrically conductive through hole.
 3. The memory card reader bodyaccording to claim 1, furthermore comprising at least one electricallyconductive track of a ground type, each extremity of which is terminatedby a connection pin situated on the internal face, said at least oneelectrically conductive track of a ground type extending from theinternal face to the external face through a third electricallyconductive through hole and from the external face to the internal facethrough a fourth electrically conductive through hole.
 4. The memorycard reader body according to claim 1, wherein the external face iscovered with a thermosetting resin.
 5. The memory card reader bodyaccording to claim 1, wherein the external face is covered with athermoplastic resin.
 6. The memory card reader body according to claim1, comprising a protective cover mounted on the external face.
 7. Thememory card reader body according to claim 6, wherein said protectivecover is sealed to the external face by a thermosetting glue orcyanoacrylate glue.
 8. The memory card reader body according to claim 1,wherein said internal face and/or said external face has at least onearea in relief on which said at least one electrically conductive trackextends.
 9. The memory card reader body according to claim 1, whereinsaid at least one electrically conductive track takes the form of a loophaving a determined geometrical shape.
 10. A memory card readercomprising the reader body according to claim
 1. 11. A terminalcomprising the memory card reader according to claim
 10. 12. A methodfor manufacturing a protective mesh of a memory card connector for amemory card reader body, wherein the method comprises: defining ageometrical shape of at least one electrically conductive trackextending on internal and external faces of said memory card reader bodyby means of at least through via passing through said internal andexternal faces; defining a location of said at least one through via;forming said at least one conductive track and said at least one throughvia on the memory card reader body.